Pd-Catalyzed Synthesis of 4-Quinolones

Significance

Reported here is a one-pot synthesis of 2-substituted 4-quinolones via Pd-catalyzed C-N coupling of primary amides with 2-bromo­acetophenones followed by base-induced intramolecular cyclization. Among the screened base/solvent combinations, NaOt-Bu in dioxane was found to be the optimal choice in the presence of Xantphos as ligand. Use of Cs₂CO₃ in polar solvents (DMF, NMP) gave mixtures of products and poor yields.